[pdfrenderer] Add some debugging capabilities. Do not compress symbol table and text data during debug.

include/tesseract/renderer.h

@@ -139,6 +139,12 @@ protected:
   // This method will grow the output buffer if needed.
   void AppendData(const char *s, int len);
 
+  template <typename T>
+  auto AppendData(T &&d) {
+    AppendData(d.data(), d.size());
+    return d.size();
+  }
+
 private:
   TessResultRenderer *next_;   // Can link multiple renderers together
   FILE *fout_;                 // output file pointer

src/api/pdfrenderer.cpp

@@ -34,6 +34,16 @@
 #include <locale>    // for std::locale::classic
 #include <memory>    // std::unique_ptr
 #include <sstream>   // for std::stringstream
+#include <string_view>
+
+using namespace std::literals;
+
+#ifndef NDEBUG
+#define DEBUG_PDF
+#endif
+#ifdef DEBUG_PDF
+#define NO_PDF_COMPRESSION
+#endif
 
 /*
 
@@ -443,6 +453,9 @@ char *TessPDFRenderer::GetPDFTextObjects(TessBaseAPI *api, double width, double
       if (fontsize != old_fontsize) {
         pdf_str << "/f-0-0 " << fontsize << " Tf ";
         old_fontsize = fontsize;
+#ifdef DEBUG_PDF
+        pdf_str << "\n";
+#endif
       }
     }
 
@@ -469,9 +482,13 @@ char *TessPDFRenderer::GetPDFTextObjects(TessBaseAPI *api, double width, double
     }
     if (word_length > 0 && pdf_word_len > 0) {
       double h_stretch = kCharWidth * prec(100.0 * word_length / (fontsize * pdf_word_len));
-      pdf_str << h_stretch << " Tz" // horizontal stretch
+      pdf_str << h_stretch << " Tz"; // horizontal stretch
+      pdf_str
           << " [ <" << pdf_word // UTF-16BE representation
           << "> ] TJ";          // show the text
+#ifdef DEBUG_PDF
+      pdf_str << "\n";
+#endif
     }
     if (last_word_in_line) {
       pdf_str << " \n";
@@ -545,26 +562,36 @@ bool TessPDFRenderer::BeginDocumentHandler() {
   for (int i = 0; i < kCIDToGIDMapSize; i++) {
     cidtogidmap[i] = (i % 2) ? 1 : 0;
   }
-  size_t len;
-  unsigned char *comp = zlibCompress(cidtogidmap.get(), kCIDToGIDMapSize, &len);
+  size_t len = kCIDToGIDMapSize;
+#ifndef NO_PDF_COMPRESSION
+  auto comp = zlibCompress(cidtogidmap.get(), kCIDToGIDMapSize, &len);
+#endif
   stream.str("");
   stream << "5 0 obj\n"
             "<<\n"
             "  /Length "
          << len
-         << " /Filter /FlateDecode\n"
+         << ""
+#ifndef NO_PDF_COMPRESSION
+            " /Filter /FlateDecode"
+#endif
+            "\n"
             ">>\n"
-            "stream\n";
+            "stream\n"
+            ;
   AppendString(stream.str().c_str());
   long objsize = stream.str().size();
+#ifndef NO_PDF_COMPRESSION
   AppendData(reinterpret_cast<char *>(comp), len);
+#else
+  AppendData(reinterpret_cast<char *>(cidtogidmap.get()), len);
+#endif
   objsize += len;
+#ifndef NO_PDF_COMPRESSION
   lept_free(comp);
-  const char *endstream_endobj =
-      "endstream\n"
-      "endobj\n";
-  AppendString(endstream_endobj);
-  objsize += strlen(endstream_endobj);
+#endif
+  objsize += AppendData("endstream\n"sv);
+  objsize += AppendData("endobj\n"sv);
   AppendPDFObjectDIY(objsize);
 
   const char stream2[] =
@@ -654,8 +681,8 @@ bool TessPDFRenderer::BeginDocumentHandler() {
   objsize = stream.str().size();
   AppendData(reinterpret_cast<const char *>(font), size);
   objsize += size;
-  AppendString(endstream_endobj);
-  objsize += strlen(endstream_endobj);
+  objsize += AppendData("endstream\n"sv);
+  objsize += AppendData("endobj\n"sv);
   AppendPDFObjectDIY(objsize);
   return true;
 }
@@ -848,29 +875,37 @@ bool TessPDFRenderer::AddImageHandler(TessBaseAPI *api) {
   // CONTENTS
   const std::unique_ptr<char[]> pdftext(GetPDFTextObjects(api, width, height));
   const size_t pdftext_len = strlen(pdftext.get());
-  size_t len;
-  unsigned char *comp_pdftext =
-      zlibCompress(reinterpret_cast<unsigned char *>(pdftext.get()), pdftext_len, &len);
-  long comp_pdftext_len = len;
+  size_t len = pdftext_len;
+#ifndef NO_PDF_COMPRESSION
+  auto comp_pdftext = zlibCompress(reinterpret_cast<unsigned char *>(pdftext.get()), pdftext_len, &len);
+#endif
   stream.str("");
   stream << obj_
          << " 0 obj\n"
             "<<\n"
             "  /Length "
-         << comp_pdftext_len
-         << " /Filter /FlateDecode\n"
+         << len
+         << ""
+#ifndef NO_PDF_COMPRESSION
+            " /Filter /FlateDecode"
+#endif
+            "\n"
             ">>\n"
-            "stream\n";
+            "stream\n"
+            ;
   AppendString(stream.str().c_str());
   long objsize = stream.str().size();
-  AppendData(reinterpret_cast<char *>(comp_pdftext), comp_pdftext_len);
-  objsize += comp_pdftext_len;
+#ifndef NO_PDF_COMPRESSION
+  AppendData(reinterpret_cast<char *>(comp_pdftext), len);
+#else
+  AppendData(reinterpret_cast<char *>(pdftext.get()), len);
+#endif
+  objsize += len;
+#ifndef NO_PDF_COMPRESSION
   lept_free(comp_pdftext);
-  const char *b2 =
-      "endstream\n"
-      "endobj\n";
-  AppendString(b2);
-  objsize += strlen(b2);
+#endif
+  objsize += AppendData("endstream\n"sv);
+  objsize += AppendData("endobj\n"sv);
   AppendPDFObjectDIY(objsize);
 
   if (!textonly_) {